Engaging the cervical spinal cord circuitry to re-enable volitional control of hand function in tetraplegic subjects

ABSTRACT

In various embodiments, methods are provided for applying transcutaneous and/or epidural spinal cord stimulation with and without selective pharmaceuticals to restore voluntary control of hand function in tetraplegic subjects.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of and priority to U.S. Ser. No.61/883,694, filed on Sep. 27, 2013, which is incorporated herein byreference in its entirety for all purposes.

STATEMENT OF GOVERNMENTAL SUPPORT

This invention was made with Government support under TR000124, awardedby the National Institutes of Health. The Government has certain rightsin the invention.

BACKGROUND

Serious spinal cord injuries (SCI) affect approximately 1.3 millionpeople in the United States, and roughly 12-15,000 new injuries occureach year. Of these injuries, approximately 50% are complete spinal cordinjuries in which there is essentially total loss of sensory motorfunction below the level of the spinal lesion.

Paralysis of the upper limbs results in an enormous loss of independenceof one's daily life. Meaningful improvement in hand function isgenerally rare after one year of tetraparesis.

SUMMARY

In various embodiments, methods are provided for applying spinal cordstimulation with and without selective pharmaceuticals to restorevoluntary control of hand function in tetraplegic subjects. The spinalcord stimulation can be transcutaneous and/or epidural. In variousembodiments the electrical stimulation alone or in combination withpharmaceuticals can be applied to facilitate restoration of motorcontrol and/or force generation in subjects suffering with spinal cordinjury and/or as other neurological injury and illness that effectsmotor control of the hand or paw. Successful application can provide adevice for widespread use in rehabilitation of neurologic injury anddisease.

In particular illustrative embodiments, the devices, optionalpharmacological agents, and methods described herein stimulate thespinal cord with, e.g., electrodes that modulate the proprioceptive andsupraspinal information that controls the hands during reaching and/orgrasping and/or manipulating conditions. Without being bound by aparticular theory, it is believed the proprioceptive and cutaneoussensory information guides the activation of the muscles in acoordinated manner and in a manner that accommodates the externalconditions.

Unlike approaches that involve specific stimulation of motor neurons todirectly induce a movement, the methods described herein can enable thespinal circuitry to control the movements. More specifically, thedevices, optional pharmacological agents, and methods described hereincan exploit the spinal circuitry and its ability to interpretproprioceptive information and to respond to that proprioceptiveinformation in a functional way. In various embodiments, this is incontrast to other approaches where the actual movement isinduced/controlled by direct stimulation (e.g., of particular motorneurons).

Accordingly, in various aspects, the invention(s) contemplated hereinmay include, but need not be limited to, any one or more of thefollowing embodiments:

Embodiment 1

A method of improving motor control and/or strength in a hand of asubject with a neuromotor disorder affecting motor control of the hand,said method including: neuromodulating the cervical spinal cord of thesubject by administering stimulation to the cervical spinal cord or aregion thereof and by administering to the subject at least onemonoaminergic agonist. In some instances of Embodiment 1, the spinalcord stimulation can be transcutaneous and/or epidural.

Embodiment 2

The method of embodiment 1, wherein said method includes administeringtranscutaneous stimulation to the cervical spinal cord or a regionthereof.

Embodiment 3

The method of embodiment 1, wherein said method includes administeringepidural stimulation to the cervical spinal cord or a region thereof.

Embodiment 4

The method of embodiment 1, wherein said method includes administering amonoaminergic agonist to said subject.

Embodiment 5

The method of embodiment 1, wherein said method includes administeringtranscutaneous stimulation to the cervical spinal cord or a regionthereof in conjunction with administration of a monoaminergic agonist.

Embodiment 6

The method of embodiment 1, wherein said method includes administeringepidural stimulation to the cervical spinal cord or a region thereof inconjunction with administration of a monoaminergic agonist.

Embodiment 7

The method of embodiment 1, wherein said method includes administeringtranscutaneous stimulation to the cervical spinal cord or a regionthereof in conjunction with epidural stimulation of the cervical spinalcord or a region thereof.

Embodiment 8

The method of embodiment 1, wherein said method includes administeringtranscutaneous stimulation to the cervical spinal cord or a regionthereof in conjunction with epidural stimulation of the cervical spinalcord or a region thereof in conjunction with administration of amonoaminergic agonist to said subject.

Embodiment 9

The method according to any one of embodiments 1, 2, 5, 7, and 8,wherein said transcutaneous stimulation is at a frequency ranging fromabout 3 Hz, or from about 5 Hz, or from about 10 Hz to about 100 Hz, orto about 80 Hz, or to about 40 Hz, or from about 3 Hz or from about 5 Hzto about 80 Hz, or from about 5 Hz to about 30 Hz, or to about 40 Hz, orto about 50 Hz.

Embodiment 10

The method according to any one of embodiments 1, 2, 5, and 7-9, whereinsaid transcutaneous stimulation is applied at an intensity ranging fromabout 10 mA to about 150 mA, or from about 20 mA to about 50 mA or toabout 100 mA, or from about 20 mA or from about 30 mA, or from about 40mA to about 50 mA, or to about 60 mA, or to about 70 mA or to about 80mA.

Embodiment 11

The method according to any one of embodiments 1, 2, 5, and 7-10,wherein said transcutaneous stimulation is at a frequency and amplitudesufficient to improve hand strength and/or fine hand control.

Embodiment 12

The method according to any one of embodiments 1, 2, 5, and 7-11,wherein said transcutaneous stimulation is applied to the dorsal aspectof the neck in the area of C5.

Embodiment 13

The method according to any one of embodiments 1, 3, and 6-12, whereinsaid epidural stimulation is at a frequency ranging from about 3 Hz, orfrom about 5 Hz, or from about 10 Hz to about 100 Hz, or to about 80 Hz,or to about 40 Hz, or from about 3 Hz or from about 5 Hz to about 80 Hz,or from about 5 Hz to about 30 Hz, or to about 40 Hz, or to about 50 Hz.

Embodiment 14

The method according to any one of embodiments 1, 3, and 6-13, whereinsaid epidural stimulation is at an amplitude ranging from 0.05 mA toabout 30 mA, or from about 0.1 mA to about 20 mA, or from about 0.1 mAto about 15 mA or to about 10 mA.

Embodiment 15

The method according to any one of embodiments 1, 3, and 6-14, whereinsaid pulse width ranges from about 150 μs to about 600 μs, or from about200 μs to about 500 μs, or from about 200 μs to about 450 μs.

Embodiment 16

The method according to any one of embodiments 1, 3, and 6-15, whereinsaid epidural stimulation is at a frequency and amplitude sufficient toimprove hand strength and/or fine hand control.

Embodiment 17

The method according to any one of embodiments 1, 3, and 6-16, whereinsaid epidural stimulation is applied paraspinally over vertebraespanning C2 to T1.

Embodiment 18

The method according to any one of embodiments 1, 3, and 6-16, whereinsaid epidural stimulation is applied paraspinally over vertebraespanning C5 to T1.

Embodiment 19

The method according to any one of embodiments 1, 3, and 6-18, whereinsaid epidural stimulation is applied via a permanently implantedelectrode array.

Embodiment 20

The method of embodiment 19, wherein said electrode array is a parylenebased microelectrode implant.

Embodiment 21

The method according to any one of embodiments 1, 4, 5, 6, and 8-20,wherein the at least one monoaminergic agonist includes a drug selectedfrom the group consisting of a serotonergic drug, a dopaminergic drug, anoradrenergic drug, a GABAergic drug, and a glycinergic drug.

Embodiment 22

The method of embodiment 21, where the agent is selected from the groupconsisting of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT),4-(benzodioxan-5-yl)1-(indan-2-yl)piperazine (S15535),N-{2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl}-N-(2-pyridinyl)cyclo-hexanecarboxamide(WAY 100.635), Quipazine, Ketanserin, 4-amino-(6-chloro-2-pyridyl)-1piperidine hydrochloride (SR 57227A), Ondanesetron, Buspirone,Methoxamine, Prazosin, Clonidine, Yohimbine,6-chloro-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol(SKF-81297),7-chloro-3-methyl-1-phenyl-1,2,4,5-tetrahydro-3-benzazepin-8-ol(SCH-23390), Quinpirole, and Eticlopride.

Embodiment 23

The method of embodiment 21, wherein said monoaminergic agonist isbuspirone.

Embodiment 24

The method of embodiment 22, wherein said drug is8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT).

Embodiment Embodiment 25

The method of embodiment 22, wherein said drug is4-(benzodioxan-5-yl)1-(indan-2-yl)piperazine (S15535).

Embodiment 26

The method of embodiment 22, wherein said drug isN-{2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl}-N-(2-pyridinyl)cyclo-hexanecarboxamide(WAY 100.635).

Embodiment 27

The method of embodiment 22, wherein said drug is Quipazine.

Embodiment 28

The method of embodiment 22, wherein said drug is Ketanserin.

Embodiment 29

The method of embodiment 22, wherein said drug is4-amino-(6-chloro-2-pyridyl)-1 piperidine hydrochloride (SR 57227A).

Embodiment 30

The method of embodiment 22, wherein said drug is Ondanesetron.

Embodiment 31

The method of embodiment 22, wherein said drug is Methoxamine.

Embodiment 32

The method of embodiment 22, wherein said drug is Prazosin.

Embodiment 33

The method of embodiment 22, wherein said drug is Clonidine.

Embodiment 34

The method of embodiment 22, wherein said drug is Yohimbine.

Embodiment 35

The method of embodiment 22, wherein said drug is 6-chloro-1-phenyl-2.

Embodiment 36

The method of embodiment 22, wherein said drug is3,4,5-tetrahydro-1H-3-benzazepine-7.

Embodiment 37

The method of embodiment 22, wherein said drug is 8-diol (SKF-81297).

Embodiment 38

The method of embodiment 22, wherein said drug is7-chloro-3-methyl-1-phenyl-1,2,4,5-tetrahydro-3-benzazepin-8-ol(SCH-23390).

Embodiment 39

The method of embodiment 21, wherein said drug is Quinpirole.

Embodiment 40

The method of embodiment 21, wherein said drug is and Eticlopride.

Embodiment 41

The method according to any one of embodiments 1 and 4-40, wherein acombination of transcutaneous and/or epidural stimulation andmonoaminergic agonist provides a synergistic improvement in handstrength and/or fine hand control.

Embodiment 42

The method according to any one of embodiments 1-41, wherein saidsubject is a human. In some embodiments, the subject is a non-humanmammal.

Embodiment 43

The method according to any one of embodiments 1-42, wherein saidsubject has a spinal cord injury.

Embodiment 44

The method of embodiment 43, wherein said spinal cord injury isclinically classified as motor complete.

Embodiment 45

The method of embodiment 43, wherein said spinal cord injury isclinically classified as motor incomplete.

Embodiment 46

The method according to any one of embodiments 1-42, wherein saidsubject has an ischemic brain injury.

Embodiment 47

The method of embodiment 46, wherein said ischemic brain injury is braininjury from stroke or acute trauma.

Embodiment 48

The method according to any one of embodiments 1-42, wherein said mammalhas a neurodegenerative pathology.

Embodiment 49

The method of embodiment 48, wherein said neurodegenerative pathology isassociated with a condition selected from the group consisting ofParkinson's disease, Huntington's disease, Alzheimer's disease,amyotrophic lateral sclerosis (ALS), primary lateral sclerosis (PLS),dystonia, and cerebral palsy.

Embodiment 50

The method according to any one of embodiments 1-49, wherein thestimulation is under control of the subject.

Embodiment 51

The method according to any one of embodiments 1-50, wherein said methodfurther includes physical training of said subject.

Embodiment 52

The method of embodiment 51, wherein said physical training includeshand contraction against a resistance.

Embodiment 53

The method according to any one of embodiments 51-52, wherein saidphysical training includes tracing a displayed pattern by handmanipulation of a hand controller.

Embodiment 54

An electrical stimulator configured to induce epidural and/ortranscutaneous electrical stimulation in the cervical region of a mammalaccording to any one of embodiments 1-20.

DEFINITIONS

As used herein “electrical stimulation” or “stimulation” meansapplication of an electrical signal that may be either excitatory orinhibitory to a muscle or neuron and/or to groups of neurons and/orinterneurons. It will be understood that an electrical signal may beapplied to one or more electrodes with one or more return electrodes.

As used herein “epidural” means situated upon the dura or in very closeproximity to the dura. The term “epidural stimulation” refers toelectrical epidural stimulation. In certain embodiments epiduralstimulation is referred to as “electrical enabling motor control”(eEmc).

The term “transcutaneous stimulation” or “transcutaneous electricalstimulation” or “cutaneous electrical stimulation” refers to electricalstimulation applied to the skin, and, as typically used herein refers toelectrical stimulation applied to the skin in order to effectstimulation of the spinal cord or a region thereof. The term“transcutaneous electrical spinal cord stimulation” may also be referredto as “tSCS”. The term “pcEmc” refers to painless cutaneous electricalstimulation.

The term “motor complete” when used with respect to a spinal cord injuryindicates that there is no motor function below the lesion, (e.g., nomovement can be voluntarily induced in muscles innervated by spinalsegments below the spinal lesion.

The term “monopolar stimulation” refers to stimulation between a localelectrode and a common distant return electrode.

The term “co-administering”, “concurrent administration”, “administeringin conjunction with” or “administering in combination” when used, forexample with respect to transcutaneous electrical stimulation, epiduralelectrical stimulation, and pharmaceutical administration, refers toadministration of the transcutaneous electrical stimulation and/orepidural electrical stimulation and/or pharmaceutical such that variousmodalities can simultaneously achieve a physiological effect on thesubject. The administered modalities need not be administered together,either temporally or at the same site. In some embodiments, the various“treatment” modalities are administered at different times. In someembodiments, administration of one can precede administration of theother (e.g., drug before electrical stimulation or vice versa).Simultaneous physiological effect need not necessarily require presenceof drug and the electrical stimulation at the same time or the presenceof both stimulation modalities at the same time. In some embodiments,all the modalities are administered essentially simultaneously.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1, panels A-I, illustrates improvement in hand function withinterventions. Assessments of grip strength were made in 6 paralyzedsubjects on 6 days of testing over 6 weeks Pre-Treatment (Phase 1, PreTreat), followed by 4 days of testing over 2 weeks with pcEMC (Phase 2,+Stim, −Busp), followed by 4 days of testing over 2 weeks with pcEMCplus oral buspirone (Phase 3, +Stim, +Busp), followed by 4 days oftesting over 2 weeks with pcEmc plus placebo (Phase 4, +Stim, −Busp),and followed by 4 days of testing over 2 weeks Post-Treatment after a3-6 month delay (Phase 5, Post Treat) (Panels A-F). Mean (±SEM) gripstrength for all 6 subjects (G), EMG amplitudes as percent increase overbaseline (Pre Treat) levels (panel H), ARAT and upper extremity ASIAfunctional scores (panel I) are shown. Horizontal lines indicatesignificant differences at P<0.05, P<0.01, or P<0.001. FD, flexordigitorum; ED, extensor digitorum; Brac, brachioradialis; Bicep, bicepsbrachii; tricep, triceps brachii.

FIG. 2, panels A-L, shows motor performance relative to eEmc parameters.Subject E (C5 injury, ASIA panel B) was implanted with a 16-channelcervical epidural stimulation paddle array spanning spinal cord levelsC5-T1, arrow pointing to electrode array (panels A and B). Prior topermanent implant, two parallel, temporary percutaneous linearelectrodes were implanted. To assess hand control, the ability toaccurately follow a targeted sign wave (panel C) and to perform rapidoscillations (panel D), and the maximal voluntary contraction (panel E)were determined during the initial day of eEmc before (Pre), during(Stim), and after (Post) stimulation (cathodes at C3 and anodes at T2,30 Hz, 3.0 mA). After permanent paddle electrode implantation,stimulation at electrodes #13 and #14 (refer to schematic in panel B)was performed with the subject passive (Baseline) and when the subjectattempted a voluntary contraction (Voluntary). Mean (±SEM, 3 trials foreach condition) grip force during Baseline and Voluntary testing atvarying stimulation frequencies (panel F) and intensities (panel G) areshown. Optimal stimulation parameters to affect hand function wereassessed (panels H-J). Time to actuate the handgrip device (responsetime) was assessed at different stimulation frequencies and intensities(±SEM, 3 trials for each condition) (panel H). The parameter of 20 Hz,0.7 mA elicited the shortest response time. Likewise, eEmc facilitatedhandgrip oscillation with doubling of oscillation ability compared toPre and Post conditions of no stimulation (representative tracingsshown) (panel I). Accuracy score during sinusoidal wave testing inresponse to varying frequencies of stimulation was assessed with thebest scores observed at 20 Hz (±SEM, 3 trials for each condition) (panelJ). Assessment of accuracy score over different sessions revealedchronic improvement with sinusoidal wave test (±SEM, 24 trials for eachcondition at electrode combinations of +13−14 and +13−6, 5-30 Hz, 0.7mA) (panel K). These improvements in hand function in response to eEmcwere evident in the acute improvements in clinical ARAT score withmulti-site electrode combination (Stim) (70% at −12+3, 30% at −12+4, 5Hz, 0.9 mA) (panel L). The improvement of 6 points in ARAT scorereflects a clinically significant event. This 20% increase reflectsimprovements in all categories measured by ARAT and is above the minimalclinically important difference of 5.7 points established for thisinstrument (van der Lee et al. (2001) J. Rehabil. Med. 33: 110-113),demonstrating the relevance of this intervention in improving upperextremity function.

FIG. 3, panels A-E, shows hand grip force and evoked potentials inSubject E. Handgrip force and EMG during a maximum handgrip performedwithout (panel A) and with eEmc (panel B) of the cervical spinal cord(electrodes +13−14, 10 Hz, 1 mA). In (panel B), the initial stimulationphase without any voluntary effort (blue shaded area), the voluntarycontraction phase (red shaded area), and the relaxation phase of thevoluntary effort (green shaded area) are shown. At least twenty evokedpotentials in each muscle were averaged during each phase. Note that anevoked potential was clearly evident in all muscles during thecontraction and relaxation phases, but only in the H. thenar during theinitial stimulation phase without any voluntary effort. The effect offrequency of stimulation on the average evoked potentials for 3 secduring the initial stimulation phase without any voluntary effort andduring the voluntary contraction phase in each muscle are shown in panelC. The data demonstrate a substantially reduced evoked response in allmuscles at the higher frequencies (20 and 30 Hz) during the voluntarycontraction phase, but no substantial loss of force. The increase inforce and two components of the EMG signal of the FD muscle during theinitial phase of contraction is shown in panel E. The iEMG is dividedinto the energy (pV.sec) derived from evoked potentials synchronizedwith the stimulation pulses (20 Hz) and the total iEMG energy, i.e., thecombination of the synchronized signals and that occurring randomly withrespect to the stimulation pulses. The samples used for plotting theforce are separated into those time bins when the EMG signals arelargely alternating in amplitude. The + sign represents bins with thelowest amplitude and the triangles represent those with the highestamplitudes. The presence or absence of the lower synchronized signal hadno impact on the force generated during a given time bin. H. Thenar,hypothenar; ER evoked response.

FIG. 4, panels A-H, shows handgrip forces and evoked responses atdifferent % maximum efforts in Subject E. Handgrip force for a maximumcontraction at the beginning of testing (100% Pre) followed by 7consecutive contractions (5 sec between each contraction, and 5 min ofrest between different efforts) at 10 (red), 25 (blue), 75 (green) %effort, and after 10 min of rest for a maximum contraction at the end oftesting (100% Post) with no stimulation (A). The FD integrated EMG(iEMG) within this series of efforts is shown in (B). Numbers above thebars in (B), (D), and (F) are linked to the contraction numbers aslabeled in (A). Fifteen min after the completion of (A), the same seriesof contractions were repeated in the presence of increasing intensitiesof stimulation ((C) and (D)). In this case, fatigue was evident at 0.7and 0.5 mA when the subject was exerting 25 and 75% effort,respectively. Stimulation at the higher intensities enabled the subjectto overcome substantial levels of fatigue. Additionally, there was anassociated increase in iEMG compared to the initial contractions withoutfatigue as well as those in which fatigue occurred (D). To determinewhether this fatigue effect was associated with repetitive contractionson the same day as in (A) and (C), on a separate day the same series ofefforts at the same level of stimulation intensities were examined. Inthis case, there was no obvious fatigue (E) at any stimulation intensityas indicated by the constant forces and only minor increases in iEMG(F). The patterns of evoked potentials at selected percent efforts andat different strengths of stimulation when there was substantial fatigueand when there was no apparent fatigue is shown in (G) and (H),corresponding to iEMG (D) and (F), respectively. In spite of the absenceof evidence of fatigue as indicated by the force with repeatedcontractions, to maintain that force may require higher intensities ofstimulation to sustain the forces generated at the end of each series ofcontractions at a given percent effort (H). Stimulation parameters wereelectrode pattern of −13+14, 20 Hz, 0-1.3 mA.

FIG. 5, panels A-F, shows sagittal T2 MRI Imaging demonstrating locationof cervical spinal cord injury of subjects A-F, approximating C2 (panelC), C5 (panels B, D, E) or C6 (panels A, F) spinal cord segment. Normaltissue at injury location is replaced by a high intensity signalrepresenting a glial scar. Spinal cord tissue distal and proximal to theinjury locus is seen to be intact without evidence of post-traumaticsyrinx formation or on-going compressive lesion.

FIG. 6, panels A-C, shows that baseline testing (Phase 1) demonstratesstable hand function by handgrip device (panel A) and ARAT and ASIAscores (panel B) prior to initiation of any intervention. Maximalhandgrip force on the last day of testing is not different from thefirst day of testing in the 6 subjects (panel A). Testing during thisphase spanned a period of 6 weeks with bi-weekly testing sessions. Eachdata point represents an average of 3 maximal handgrip contractions.Clinical testing by ARAT and ASIA scores demonstrated no evidence ofimprovement during this initial baseline testing period (panel B).

FIG. 7, panels A-I, show amplitudes of spinal cord evoked potentialsinduced by cathode-anode epidural electrode pairs with a range ofcurrents and frequencies starting from the rostral to caudal spinal cord(refer to FIG. 2B for electrode configuration). The amplitude of thepotentials demonstrates the relative responsiveness of each motor poolto the stimulation at a specific spinal location at a given level ofcurrent and frequency. The cathode-anode pair of −13+14 produced themost activation of muscles associated with hand function, i.e., H.Thenar and FD, and was used for most of the study.

FIG. 8 shows upper extremity motor ASIA Impairment Score of Subject E.Motor function was assessed at the beginning and conclusion of thestudy, demonstrating a clinically significant 23-point increase duringthe study period.

DETAILED DESCRIPTION

Embodiments described herein provide methods for applying spinal cordstimulation with and without selective pharmaceuticals to restorevoluntary control of upper extremity function in tetraplegic subjects.In some embodiments, the upper extremity or extremities can be thehands. The spinal cord stimulation can be transcutaneous, epidural, or acombination thereof. The spinal cord stimulation alone or in combinationwith pharmaceuticals can be applied to facilitate restoration of motorcontrol and/or force generation in individuals with spinal cordinjuries.

As demonstrated herein in the Examples, an injured cervical spinal cord(e.g., a human cervical spinal cord) can be modulated using painlesscutaneous electrical stimulation (pcEmc), monoaminergic agonist (fEmc)treatment, and/or eEmc to regain voluntary hand function. In someembodiments, mean hand strength can be increased by greater than 300%after pcEmc plus fEmc (buspirone) treatment. This was demonstrated in 6subjects with a chronic motor complete cervical injury. One subject thatwas implanted with a cervical epidural electrode array realizedsignificantly improved hand strength and fine hand control in thepresence of cervical eEmc. Thus, the cervical circuitry can beneuromodulated to improve volitional control of hand function intetraplegic subjects with one or more interventions: transcutaneouselectrical stimulation (e.g., pcEMC), and/or monoaminergic agonistadministration (fEmc), and/or epidural electrical stimulation (eEmc). Insome embodiments, the impact of the herein described methods onindividuals with upper limb paralysis can be dramatic functionally,psychologically, and economically.

Accordingly, in various embodiments, methods are provided for improvingmotor control and/or strength in a hand (or paw) of a subject with aneuromotor disorder affecting motor control of the hand (or paw). Invarious embodiments, the methods involve neuromodulating the cervicalspinal cord of the subject by administering transcutaneous stimulationto the cervical spinal cord or a region thereof and/or neuromodulatingthe cervical spinal cord of said subject by administering epiduralstimulation to the cervical spinal cord or a region thereof; and/or byadministering to the subject a monoaminergic agonist (or otherneuromodulatory pharmaceutical).

In some embodiments, neuromodulatory strategies can be used to improvefine motor control of the upper limbs, i.e., performance of motor tasksconsidered to be less “automatic” than posture and locomotion. Thesestrategies can neuromodulate the lumbosacral spinal circuitry viaepidural stimulation (electrical enabling motor control, eEmc)

In various embodiments, these methods can, optionally, be used incombination with physical training regimen. And in some embodiments, thepharmaceutical can be buspirone.

The methods described herein are for use with a mammal (e.g., a human, amammal (e.g., a non-human primate, equine, feline, canus, etc.) who hasa spinal cord with at least one dysfunctional spinal circuit thatinhibits motor control and/or strength in a hand or paw and/or whoexhibits another neuropathology that inhibits motor control and/orstrength in a hand or paw. In one embodiment, the mammal is a human. Asdescribed herein, ranscutaneous electrical stimulation of the cervicalspinal cord or a region thereof, and/or epidural stimulation of thecervical spinal cord, or a region thereof, and/or use of aneuromodulatory agent (e.g., a monoaminergic agent) can improve and/orrestore motor control and/or strength to a hand or paw.

In some embodiments, hand function can be improved by neuromodulatingthe cervical spinal cord. Six subjects with chronic (18-36 months)spinal cord injury (SCI, traumatic cervical injury, ASIA B with no motorstrength below the injury) were tested. All subjects initially hadminimal hand strength, a condition characteristic of the majority ofcervical SCI patients. The experimental approach began with six weeks ofbaseline testing (Phase 1), followed by three 2-week treatment periods(phases 2-4), and then by a period of approximately three months withoutany treatment at the end of which there was a final two week testingperiod (Phase 5). pcEmc at the C5 spinal segment (Phase 2) increasedhand strength in 4/6 subjects compared to baseline Phase 1. Duringbuspirone treatment (Phase 3), 4/6 subjects increased hand strengthcompared to Phase 1 and 2. The next 2 weeks buspirone was withdrawn butpcEmc continued (Phase 4), and again 4/6 subjects showed furtherimprovement in grip strength compared to Phase 3. For all subjectscombined, the mean grip strength tended to increase after eachsuccessive treatment phase. EMG amplitudes were generally consistentwith increases in grip force, i.e., digit flexor and extensor EMGamplitudes tended to increase progressively across phases. Afterapproximately three months without treatment, 4/6 subjects improvedtheir performance relative to Phase 4.

These results show that the cervical spinal cord can be neuromodulatedusing two paradigms, i.e., electrically and pharmacologically. Moreover,these data indicate that non-functional networks can become engaged andprogressively improve motor performance. In addition, the furtherimprovement in hand function after withdrawing pcEMC and fEMC suggeststhat once functional connections are established they remain active.

Accordingly, the methods described herein are useful to improve and/orrestore motor function to the hand or paw of a subject having paralysisaffecting that hand or paw. In various embodiments, the methods providethat the spinal circuitry is neuromodulated to a physiological statethat facilitates or enables the recovery or improved control of movementor improved strength of a hand or paw following some neuromotordysfunction.

In some embodiments the paralysis effecting the hand or paw may be amotor complete paralysis or a motor incomplete paralysis. In certainembodiments the paralysis may have been caused by a spinal cord injuryclassified as motor complete or motor incomplete. The paralysis may havebeen caused by an ischemic or traumatic brain (or spinal) injury. Incertain embodiments the paralysis may have been caused by an ischemicbrain injury resulting from a stroke or acute trauma. By way of anotherexample, the paralysis may have been caused by a neurodegenerativecondition affecting the brain and/or spinal cord. In certain embodimentsthe neurodegenerative injury may be associated with a disease such asParkinson's disease, Huntington's disease, Alzheimer's disease,frontotemporal dementia, dystonia, amyotrophic lateral sclerosis (ALS),primary lateral sclerosis (PLS), and other conditions such as cerebralpalsy and multiple sclerosis (MS).

By way of non-limiting example, in certain embodiments, the methodsdescribed herein comprises application of electrical stimulation to thecervical spinal cord or a portion thereof of the subject. The electricalstimulation may be applied by a surface electrode(s) that is applied tothe skin surface of the subject to provide a transcutaneous stimulation.Additionally, or alternatively, the electrical stimulation can beprovided epidurally (e.g., via an implanted electrode or electrodearray).

In various embodiments, the electrodes may; be implanted along, and/orthe stimulation may be applied to the entire cervical spine (e.g.,C1-T1) or to a region therein (e.g., C2-C7, C3-C7, C3-C6, C3-C5, C4-C7,C4-C6, C4-C5, C5, etc.). The electrical stimulation is delivered, e.g.,as described herein (e.g., at 5-40 Hz at 20-100 mA). While not arequirement, the electrical stimulation may not directly activate musclecells in the portion of the patient's body having the paralysis. Incertain embodiments the electrodes (surface and/or implanted) mayinclude an array of one or more electrodes stimulated in a monopolarbiphasic configuration.

In various embodiments, the stimulation may include tonic stimulationand/or intermittent stimulation. The stimulation may includesimultaneous or sequential stimulation, or combinations thereof, ofdifferent cord regions (e.g., different regions within the cervicalspinal cord, or a region within the cervical spinal cord and anotherregions outside the cervical spinal cord). Optionally, in certainembodiments, the stimulation pattern may be under control of thesubject.

In certain embodiments, the method(s) may include administering one ormore neuropharmaceutical agents to the subject. The neuropharmaceuticalagents may include, for example, a monoaminergic agent (e.g.,buspirone).

In certain embodiments, the electrical stimulation is defined by a setof parameter values (e.g., frequency, amplitude, pulse width, etc.), andactivation of the selected spinal circuit may (but need not) generate aquantifiable result. Optionally, the method may be repeated usingelectrical stimulation having different sets of parameter values toobtain quantifiable results generated by each repetition of the method.In certain embodiments a machine learning method may be executed by atleast one computing device. The machine learning method builds a modelof a relationship between the electrical stimulation applied to thespinal cord and the quantifiable results generated by activation of theat least one spinal circuit. A new set of parameters may be selectedbased on the model. By way of a non-limiting example, the machinelearning method may implement a Gaussian Process Optimization, e.g., asdescribed in PCT Publication No: WO/2012/094346 (PCT/US2012/020112).

In various embodiments, the methods described herein may furtherincorporate physical training In certain embodiments, the physicaltraining may include inducing a resistance-providing positional changein the region of the subject where locomotor activity is to befacilitated (e.g., the hand and/or finger(s)). The positional change inthe subject may include, but need not be limited to grasping and/ortracking. In certain embodiments, the physical training may includerobotically guided training

Another exemplary embodiment is a method that includes placing anelectrode on the subject's cervical spinal cord, positioning the patientin a training device configured to assist with physical training that isconfigured to induce neurological signals in the hand or paw, andapplying electrical stimulation to a portion of the cervical spinal cordof the subject.

Transcutaneous Stimulation of a Region of the Cervical Spine

The location of the electrode and its stimulation parameters areimportant in defining motor response. Use of surface electrode(s), asdescribed herein, facilitates selection or alteration of particularstimulation sites as well as the application of a wide variety ofstimulation parameters. Additionally surface stimulation can be used tooptimize location for an implantable electrode or electrode array forepidural stimulation.

In various embodiments, the methods described herein involvetranscutaneous electrical stimulation of the cervical spine or a regionof the cervical spine of the subject. Illustrative regions include, butare not limited to one or more regions straddling or spanning a regionselected from the group consisting of C1-C1, C1-C2, C1-C3, C1-C4, C1-C7,C1-C6, C1-C7, C1-T1, C2-C2, C2-C3, C2-C4, C2-C5, C2-C6, C2-C7, C2-T1,C3-C3, C3-C4, C3-C5, C3-C6, C3-C7, C3-T1, C4-C4, C4-C5, C4-C6, C4-C7,C4-T1, C5-C5, C5-C6, C5-C7, C5-T1, C6-C6, C6-C7, C6-T1, C7-C7, andC7-T1.

In certain embodiments, the stimulation is stimulation at a frequencyranging from about 3 Hz, or from about 5 Hz, or from about 10 Hz toabout 100 Hz, or to about 80 Hz, or to about 40 Hz, or from about 3 Hzor from about 5 Hz to about 80 Hz, or from about 5 Hz to about 30 Hz, orto about 40 Hz, or to about 50 Hz.

In certain embodiments, the transcutaneous stimulation is applied at anintensity ranging from about 10 mA to about 150 mA, or from about 20 mAto about 50 mA or to about 100 mA, or from about 20 mA or from about 30mA, or from about 40 mA to about 50 mA, or to about 60 mA, or to about70 mA or to about 80 mA.

In certain embodiments, the transcutaneous stimulation is at a frequencyand amplitude sufficient to improve hand strength and/or fine handcontrol when applied in conjunction with a neuromodulatory agent (e.g.,a monoaminergic agent). In certain embodiments the transcutaneousstimulation is at a frequency and amplitude sufficient to improve handstrength and/or fine hand control when applied in conjunction with anepidural stimulation of the cervical spinal cord or a region thereof. Incertain embodiments the transcutaneous stimulation is at a frequency andamplitude sufficient to improve hand strength and/or fine hand controlwhen applied in conjunction with a neuromodulatory agent (e.g., amonoaminergic agent) and epidural stimulation of the cervical spinalcord or a region thereof. In certain embodiments the transcutaneousstimulation is at a frequency and amplitude sufficient to improve handstrength and/or fine hand control when utilized without epiduralstimulation and/or without a neuromodulatory agent.

Epidural Stimulation of a Region of the Cervical Spine

In various embodiments, the methods described herein involve epiduralelectrical stimulation of the cervical spine or a region of the cervicalspine of the subject. Illustrative regions include, but are not limitedto, one or more regions straddling or spanning a region selected fromthe group consisting of C1-C1, C1-C2, C1-C3, C1-C4, C1-C7, C1-C6, C1-C7,C1-T1, C2-C2, C2-C3, C2-C4, C2-C5, C2-C6, C2-C7, C2-T1, C3-C3, C3-C4,C3-C5, C3-C6, C3-C7, C3-T1, C4-C4, C4-C5, C4-C6, C4-C7, C4-T1, C5-C5,C5-C6, C5-C7, C5-T1, C6-C6, C6-C7, C6-T1, C7-C7, and C7-T1.

In certain embodiments, the epidural stimulation is at a frequencyranging from about 3 Hz, or from about 5 Hz, or from about 10 Hz toabout 100 Hz, or to about 80 Hz, or to about 40 Hz, or from about 3 Hzor from about 5 Hz to about 80 Hz, or from about 5 Hz to about 30 Hz, orto about 40 Hz, or to about 50 Hz.

In certain embodiments, the epidural stimulation is at an amplituderanging from 0.05 mA to about 30 mA, or from about 0.1 mA to about 20mA, or from about 0.1 mA to about 15 mA or to about 10 mA.

In certain embodiments, the pulse width ranges from about 150 μs toabout 600 μs, or from about 200 μs to about 500 μs, or from about 200 μsto about 450 μs.

In certain embodiments, the epidural stimulation is at a frequency andamplitude sufficient to improve hand strength and/or fine hand control.In certain embodiments the epidural stimulation is applied paraspinallyover a cervical region identified above (e.g., over vertebrae spanningC2 to T1, over vertebrae spanning C5 to T1, etc.).

In certain embodiments, the epidural stimulation is applied via apermanently implanted electrode array (e.g., a typical density electrodearray, a high density electrode array, etc.).

In certain embodiments, the epidural electrical stimulation isadministered via a high density epidural stimulating array (e.g., asdescribed in PCT Publication No: WO/2012/094346 (PCT/US2012/020112). Incertain embodiments, the high density electrode arrays are preparedusing microfabrication technology to place numerous electrodes in anarray configuration on a flexible substrate. In some embodiments,epidural array fabrication methods for retinal stimulating arrays can beused in the methods described herein (see, e.g., Maynard (2001) Annu.Rev. Biomed. Eng., 3: 145-168; Weiland and Humayun (2005) IEEE Eng. Med.Biol. Mag., 24 (5): 14-21, and U.S. Patent Publications 2006/0003090 and2007/0142878). In various embodiments, the stimulating arrays compriseone or more biocompatible metals (e.g., gold, platinum, chromium,titanium, iridium, tungsten, and/or oxides and/or alloys thereof)disposed on a flexible material. Flexible materials can be selected fromparylene A, parylene C, parylene AM, parylene F, parylene N, parylene D,other flexible substrate materials, or combinations thereof. Parylenehas the lowest water permeability of available microfabricationpolymers, is deposited in a uniquely conformal and uniform manner, haspreviously been classified by the FDA as a United States Pharmacopeia(USP) Class VI biocompatible material (enabling its use in chronicimplants) (Wolgemuth, Medical Device and Diagnostic Industry, 22 (8):42-49 (2000)), and has flexibility characteristics (Young's modulus ˜4GPa (Rodger and Tai (2005) IEEE Eng. Med. Biology, 24 (5): 52-57)),lying in between those of PDMS (often considered too flexible) and mostpolyimides (often considered too stiff). Finally, the tear resistanceand elongation at break of parylene are both large, minimizing damage toelectrode arrays under surgical manipulation. The preparation andparylene microelectrode arrays suitable for use in the epiduralstimulation methods described herein is described in PCT Publication No:WO/2012/100260 (PCT/US2012/022257).

The electrode array may be implanted using any of a number of methods(e.g., a laminectomy procedure) well known to those of skill in the art.

In various embodiments, the arrays are operably linked to controlcircuitry that permits selection of electrode(s) to activate/stimulateand/or that controls frequency, and/or pulse width, and/or amplitude ofstimulation. In various embodiments, the electrode selection, frequency,amplitude, and pulse width are independently selectable, e.g., atdifferent times, different electrodes can be selected. At any time,different electrodes can provide different stimulation frequenciesand/or amplitudes. In various embodiments, different electrodes or allelectrodes can be operated in a monopolar mode and/or a bipolar mode,using constant current or constant voltage delivery of the stimulation.

In certain embodiments, the electrodes can also be provided withimplantable control circuitry and/or an implantable power source. Invarious embodiments, the implantable control circuitry can beprogrammed/reprogrammed by use of an external device (e.g., using ahandheld device that communicates with the control circuitry through theskin). The programming can be repeated as often as necessary.

Any present or future developed stimulation system capable of providingan electrical signal to one or more regions of the cervical spinal cordmay be used in accordance with the teachings provided herein. In variousembodiments, the system may comprise an external pulse generator. Inother embodiments the system may comprise an implantable pulse generatorto produce a number of stimulation pulses that are sent to the a regionin proximity to the cervical spinal cord by insulated leads coupled tothe spinal cord by one or more electrodes and/or an electrode array. Incertain embodiments the one or more electrodes or one or more electrodescomprising the electrode array may be attached to separate conductorsincluded within a single lead. Any known or future developed lead usefulfor applying an electrical stimulation signal in proximity to asubject's spinal cord may be used. For example, the leads may beconventional percutaneous leads, such as PISCES® model 3487A sold byMedtronic, Inc. In some embodiments, it may be desirable to employ apaddle-type lead.

Any known or future developed external or implantable pulse generatormay be used in accordance with the teachings provided herein. Forexample, one internal pulse generator may be an ITREL® II or Synergypulse generator available from Medtronic, Inc, Advanced NeuromodulationSystems, Inc.'s GENESIS™ pulse generator, or Advanced BionicsCorporation's PRECISION™ pulse generator. One of skill in the art willrecognize that the above-mentioned pulse generators may beadvantageously modified to deliver therapy in accordance with theteachings provided herein.

In certain embodiments systems can employ a programmer coupled via aconductor to a radio frequency antenna. This system permits attendingmedical personnel to select the various pulse output options afterimplant using radio frequency communications. While, in certainembodiments, the system employs fully implanted elements, systemsemploying partially implanted elements may also be used in accordancewith the teachings provided herein.

In one illustrative, but non-limiting system, a control module isoperably coupled to a signal generation module and instructs the signalgeneration module regarding the signal to be generated. For example, atany given time or period of time, the control module may instruct thesignal generation module to generate an electrical signal having aspecified pulse width, frequency, intensity (current or voltage), etc.The control module may be preprogrammed prior to implantation or receiveinstructions from a programmer (or another source) through any known orfuture developed mechanism, such as telemetry. The control module mayinclude or be operably coupled to memory to store instructions forcontrolling the signal generation module and may contain a processor forcontrolling which instructions to send to signal generation module andthe timing of the instructions to be sent to signal generation module.In various embodiments, leads are operably coupled to signal generationmodule such that a stimulation pulse generated by signal generationmodule may be delivered via electrodes.

While in certain embodiments, two leads are utilized, it will beunderstood that any number of one or more leads may be employed. Inaddition, it will be understood that any number of one or moreelectrodes per lead may be employed. Stimulation pulses are applied toelectrodes (which typically are cathodes) with respect to a returnelectrode (which typically is an anode) to induce a desired area ofexcitation of electrically excitable tissue in a region of the cervicalspine. A return electrode such as a ground or other reference electrodecan be located on same lead as a stimulation electrode. However, it willbe understood that a return electrode may be located at nearly anylocation, whether in proximity to the stimulation electrode or at a moreremote part of the body, such as at a metallic case of a pulsegenerator. It will be further understood that any number of one or morereturn electrodes may be employed. For example, there can be arespective return electrode for each cathode such that a distinctcathode/anode pair is formed for each cathode.

The epidural electrode stimulation systems described herein are intendedto be illustrative and non-limiting. Using the teachings providedherein, alternative epidural stimulation systems and methods will beavailable to one of skill in the art.

Use of Neuromodulatory Agents

In certain embodiments, the transcutaneous and/or epidural stimulationmethods described herein are used in conjunction with variouspharmacological agents, particularly pharmacological agents that haveneuromodulatory activity (e.g., are monoamergic). In certainembodiments, the use of various serotonergic, and/or dopaminergic,and/or noradrenergic, and/or GABAergic, and/or glycinergic drugs iscontemplated. These agents can be used in conjunction with epiduralstimulation and/or transcutaneous stimulation and/or physical therapy asdescribed above. This combined approach can help to put the spinal cord(e.g., the cervical spinal cord) in an optimal physiological state forcontrolling a range of hand movements.

In certain embodiments, the drugs are administered systemically, whilein other embodiments, the drugs are administered locally, e.g., toparticular regions of the spinal cord. Drugs that modulate theexcitability of the spinal neuromotor networks include, but are notlimited to combinations of noradrenergic, serotonergic, GABAergic, andglycinergic receptor agonists and antagonists.

Dosages of at least one drug or agent can be between about 0.001 mg/kgand about 10 mg/kg, between about 0.01 mg/kg and about 10 mg/kg, betweenabout 0.01 mg/kg and about 1 mg/kg, between about 0.1 mg/kg and about 10mg/kg, between about 5 mg/kg and about 10 mg/kg, between about 0.01mg/kg and about 5 mg/kg, between about 0.001 mg/kg and about 5 mg/kg, orbetween about 0.05 mg/kg and about 10 mg/kg.

Drugs or agents can be delivery by injection (e.g., subcutaneously,intravenously, intramuscularly), orally, rectally, or inhaled.

Illustrative pharmacological agents include, but are not limited to,agonists and antagonists to one or more combinations of serotonergic:5-HT1A, 5-HT2A, 5-HT3, and 5HT7 receptors; to noradrenergic alpha 1 and2 receptors; and to dopaminergic D1 and D2 receptors (see, e.g., Table1).

TABLE 1 Illustrative pharmacological agents. Typical Typical Dose RangeName Target Action Route (mg/Kg) (mg/kg) Serotonergic receptor systems8-OHDPAT 5-HT1A7 Agonist S.C. 0.05 0.045-0.3  Way 100.635 5-HT1AAntagonist I.P. 0.5 0.4-1.5 Quipazine 5-HT2A/C Agonist I.P. 0.20.18-0.6  Ketanserin 5-HT2A/C Antagonist I.P. 3 1.5-6.0 SR 57227A 5-HT3Agonist I.P. 1.5 1.3-1.7 Ondanesetron 5-HT3 Antagonist I.P. 3 1.4-7.0SB269970 5-HT7 Antagonist I.P. 7  2.0-10.0 Noradrenergic receptorsystems Methoxamine Alpha1 Agonist I.P. 2.5 1.5-4.5 Prazosin Alpha1Antagonist I.P. 3 1.8-3.0 Clonidine Alpha2 Agonist I.P. 0.5 0.2-1.5Yohimbine Alpha2 Antagonist I.P. 0.4 0.3-0.6 Dopaminergic receptorsystems SKF-81297 D1-like Agonist I.P. 0.2 0.15-0.6  SCH-23390 D1-likeAntagonist I.P. 0.15  0.1-0.75 Quinipirole D2-like Agonist I.P. 0.30.15-0.3  Eticlopride D2-like Antagonist I.P. 1.8 0.9-1.8

The foregoing methods are intended to be illustrative and non-limiting.Using the teachings provided herein, other methods involvingtranscutaneous electrical stimulation and/or epidural electricalstimulation and/or the use of neuromodulatory agents to improve motorcontrol and/or strength of a hand or paw will be available to one ofskill in the art.

EXAMPLES

The following examples are offered to illustrate, but not to limit theclaimed invention.

Example 1 Engaging the Cervical Spinal Cord Circuitry to Re-EnableVolitional Control of Hand Function in Tetraplegic Patients

The present Example demonstrates whether herein describedneuromodulatory strategies can be used to improve fine motor control ofthe upper limbs, i.e., performance of motor tasks considered to be less“automatic” than posture and locomotion. Here we show that the injuredhuman cervical spinal cord can be modulated using painless cutaneouselectrical stimulation (pcEmc), monoaminergic agonist (fEmc) treatment,and/or eEmc to regain voluntary hand function. Mean hand strengthincreased greater than 300% after pcEmc plus fEmc (buspirone) treatmentin 6 subjects with a chronic motor complete cervical injury. One subjectthat was implanted with a cervical epidural electrode array realizedsignificantly improved hand strength and fine hand control in thepresence of cervical eEmc. Thus, we now demonstrate that the cervicalcircuitry can be neuromodulated to improve volitional control of handfunction in tetraplegic subjects with three novel interventions. Theimpact of these observations on individuals with upper limb paralysiscould be dramatic functionally, psychologically, and economically.

Six subjects with chronic (18-36 months) spinal cord injury (SCI,traumatic cervical injury, ASIA B with no motor strength below theinjury) were tested to determine if hand function can be improved byneuromodulating the cervical spinal cord. All subjects initially hadminimal hand strength, a condition reflecting the majority of cervicalSCI patients. Our experimental approach began with 6 weeks of baselinetesting (Phase 1), followed by three 2-week treatment periods (Phases2-4), and then by a period of approximately three months without anytreatment at the end of which there was a final 2-week testing period(Phase 5). pcEmc at the C5 spinal segment (Phase 2) increased handstrength in 4/6 subjects compared to baseline Phase 1 (FIG. 1, panelsA-G). During buspirone treatment (Phase 3), 4/6 subjects increased handstrength compared to Phase 1 and 2. The next 2 weeks buspirone waswithdrawn but pcEmc continued (Phase 4), and again 4/6 subjects showedfurther improvement in grip strength compared to Phase 3. For allsubjects combined, the mean grip strength tended to increase after eachsuccessive treatment phase (FIG. 1, panel G). EMG amplitudes weregenerally consistent with increases in grip force, i.e., digit flexorand extensor EMG amplitudes tended to increase progressively acrossphases (FIG. 1, panel H). After approximately three months withouttreatment, 4/6 subjects improved their performance relative to Phase 4.

These results show that the cervical spinal cord can be neuromodulatedusing two paradigms, i.e., electrically and pharmacologically. In someembodiments, the present methods are highly interactive and perhapssynergistic. Synergy and interactivity were observed in animalexperiments. These data suggest that non-functional networks can becomeengaged and progressively improve motor performance. In someembodiments, further improvement in hand function after withdrawingpcEMC and fEMC can be a result of functional connections remainingactive once they are established.

The improvements are unlikely to be due to natural recovery or fromrepeated practice as large cohort studies of SCI patients havedemonstrated that the majority of functional improvements occur within 6months of the injury and that minimal recovery of function is observedpast the 12 month time-point. All of our subjects were 18 months beyondthe initial injury when recruited. Furthermore, baseline motor functiontesting for 6 weeks prior to any therapeutic intervention revealedstable function (FIG. 6). Concomitant to significantly improved handstrength, gains in upper extremity functional metrics by ARAT (13 pointimprovement) and ASIA (7 point improvement) tests, reflecting the impactof these interventions on the patient's overall upper extremity motorfunction (FIG. 1, panel I).

Given the results above, we then asked whether the cervical spinalcircuitry could be neuromodulated to improve hand function bystimulating via an epidural array implant (implanted in subject shown inFIG. 1, panel E). The implanted stimulating electrodes spanned thecaudal portion of C5 to the rostral portion of T1 (FIG. 2, panel A,arrow; FIG. 2, panel B, electrode diagram). After mapping of thecervical motor pools by spinal cord evoked potentials (FIG. 7) we mainlyused electrodes 13 and 14 to modulate hand function (FIG. 2, panel B,shaded boxes).

In the initial acute phase after implantation of a temporary trialarray, the subject's ability to accurately follow a targeted forcepresented with a cursor moving in a sine wave pattern on a video screenwas improved with eEmc (FIG. 2, panel C). The subject also couldgenerate a more rapid oscillating force above and below a pre-selectedtarget force in the presence of stimulation (FIG. 2, panel D).Additionally handgrip force was increased with stimulation at 5 and 30Hz (FIG. 2, panel E). Importantly, some of these improvements wereobserved after stimulation.

After implantation of the permanent electrode array, we next performed aseries of motor tests over the next 9 months comparing the effects ofdifferent stimulation parameters in facilitating maximum force and finecontrol. Maximal forces were generated at 10-20 Hz (FIG. 2, panel F) and0.7-1.3 mA (FIG. 2, panel G). These forces were lower than the forcegenerated in normal subjects (approximately 400 N), but substantiallymore than baseline. Evidence of the importance of selecting the optimalfrequency and intensity of stimulation was reflected in the time that ittook to respond to a signal to begin generating a force (FIG. 2, panelH). However, there were extremely long delays (sec) relative touninjured subjects (approximately 200 ms) in voluntarily initiating aforce regardless of the stimulation parameters. We compared theperformance of these motor tasks to a commonly used clinical assessmenttool and found a 6-point increase in ARAT with eEmc on vs. off duringthe same testing session, demonstrating the clinical relevance (FIG. 2,panel L).

Accuracy in controlling force was performed approximately weekly over aperiod of eight months to identify the optimal stimulation parameters.Rapid oscillatory movements were performed at 20 Hz and 0.5 mA and at 10and 30 Hz and 0.7 mA (FIG. 2, panel I). Accuracy in following a targetedforce occurred at 20 Hz (FIG. 2, panel J). In addition, the accuracy ofcontrolling force in a sine wave pattern almost doubled over a two-monthperiod (FIG. 2, panel K).

The present methods and systems provide that: 1) optimal stimulationparameters generating the highest forces differed from those generatingthe greatest accuracy at sub-maximal forces; 2) effects of stimulationintensity and frequency on maximum force production and accuracy arehighly interdependent; 3) accuracy of force generation can be improvedover time in the presence of eEmc; and 4) time needed to initiate aforce following a command was prolonged, but could be improved withspecific stimulation parameters. Each of these observations demonstratesthe importance of matching the stimulation parameters with the task tobe performed. In some embodiments, eEmc can yield improvement (e.g.,meaningful) in upper extremity function in subjects with a cervical SCI.

Accuracy in controlling force was performed approximately weekly over aperiod of eight months to identify the optimal stimulation parameters.Rapid oscillatory movements were performed at 20 Hz and 0.5 mA and at 10and 30 Hz and 0.7 mA (FIG. 2, panel I). Accuracy in following a targetedforce occurred at 20 Hz (FIG. 2, panel J). In addition, the accuracy ofcontrolling force in a sine wave pattern almost doubled over a two-monthperiod (FIG. 2, panel K).

The present methods and systems provide that: 1) optimal stimulationparameters generating the highest forces differed from those generatingthe greatest accuracy at sub-maximal forces; 2) effects of stimulationintensity and frequency on maximum force production and accuracy arehighly interdependent; 3) accuracy of force generation can be improvedover time in the presence of eEmc; and 4) time needed to initiate aforce following a command was prolonged, but could be improved withspecific stimulation parameters. Each of these observations demonstratesthe importance of matching the stimulation parameters with the task tobe performed. In some embodiments, eEmc can yield improvement (e.g.,meaningful) in upper extremity function in subjects with a cervical SCI.

A dysfunctional interaction may exist between supraspinal and sensorynetworks given the externally imposed neuromodulation of the spinalcircuitry and since neither the descending motor control nor the spinalcircuitry had functioned in any significant interactive way since theinjury. This interaction was explored between supraspinally deriveddescending volitional drive and sensory-derived input to the spinalnetworks and motor pools when the spinal circuitry was beingneuromodulated with eEmc.

Could supraspinal networks volitionally accommodate the ‘level ofeffort’ to the level of motor pool excitability imposed by eEmc? Toaddress this question we asked the subject to generate a series of sevencontractions at different levels of maximum efforts with and withoutstimulation (FIG. 4). Without stimulation, the force level wasmaintained for all seven contractions at the lowest percentage effort,but force declined during the later contractions at the higherpercentage efforts (FIG. 4, panel A). Over a wide range of stimulationintensities at the lowest percent effort, there were no markeddifferences in the subject's ability to estimate a target force (FIG. 4,panel C). At higher percent efforts fatigue was evident at moderatestimulation intensities, but this was overcome at the higher levels ofstimulation, suggesting a neural deficit (FIG. 4, panels A and C). Werepeated the experiments shown in FIG. 4, panels A and C (which occurredwithin 15 min period) on another day to avoid possible neuromuscularfatigue (FIG. 4, panel E). At the lower percent effort withoutstimulation, there was greater recruitment during the later contractionsthat enabled a constant force, whereas at the higher percent efforts thesubject was unable to compensate with greater recruitment (FIG. 4, panelB). With stimulation, however, even at the higher efforts the targetedforce could be reached as the result of greater motor pool excitation(FIG. 4, panel D). A similar but less dramatic change in excitation ofthe motor pools was present even when the targeted forces were reachedat the different percent efforts (FIG. 4, panels D, F-H). In spite ofthe wide range in levels of neuromodulation there was remarkableconsistency in volitionally generated forces. These results suggest thatthe subjects consciously perceived rather accurately the combinedphysiological state of supraspinal, spinal, and sensory networks toachieve the targeted levels of force simply defined conceptually as a“percent maximum effort” even in the presence of fatigue.

PcEmc, fEmc, and eEmc interventions can enhance the level ofexcitability of pre-motor spinal circuitries that mediate hand function.The importance of these data is that they identify three novelinterventional strategies having significant potential for high clinicalimpact in a relatively short timeframe on a function considered to be ofhighest priority among paralyzed patients. The impact of these resultsis significant from the following perspectives: 1) neuromodulation isnot dependent on the physiological phenomenon of central patterngeneration but also applies to fine neuromotor control of less“automatic” movements; 2) they raise the possibility that theneuromodulatory concept could apply to other neural networks andtherefore could be applied to neuromotor disorders such as stroke andParkinson disease; and 3) they demonstrate the potential of enhancingmaximum neuromuscular force, as well as fine control of movements. Theimproved force potential was associated with improved performance inupper extremity tasks (ARAT). Importantly, even after more than a yearof inactivity of the sensorimotor circuits, significant levels ofactivity-dependent plasticity persist.

Methods Summary

The University of California, Los Angeles Institutional Review Boardapproved all procedures. Subjects were enrolled based on the enrollmentcriteria of traumatic cervical injury, ASIA B, greater than 1 year frominjury, and stable motor function as documented by sequential clinicalexams. Baseline clinical scores (ARAT, ASIA) prior to study interventionwere assessed (FIG. 1, panel I).

Voluntary motor control data were assessed using a handgrip forcemeasurement device. EMG data were collected via surface electrodesplaced unilaterally on upper extremity muscles. Stimulation and datacollection was obtained using the Konigsberg EMG system (Konigsberg,Pasadena, Calif.). Functional assessments by validated assessment toolswere performed weekly during each study phase: American Spinal InjuryAssessment (ASIA), and Action Research Arm Test (ARAT) (Carroll (1965)J. Chronic Dis., 18: 479-491). Two blinded examiners conducted thefunctional tests.

The transcutaneous stimulation device is non-invasive. Stimulationparameters ranged from 5-30 Hz and 20-100 mA, located at C5. From themidpoint of Phase 1 to the end of Phase 4 all subjects were informedthat they would receive either a placebo or the monoaminergic agonist(7.5 mg buspirone twice daily for 2 weeks beginning the day beforebiweekly testing). All subjects received buspirone during Phase 3 and aplacebo during Phases 1, 2, and 4. All subjects and testers wereblinded.

A temporary trial with two 16-contact percutaneous epidural leads(Linear Lead, Boston Scientific, Valencia, Calif.) spanning C2 to T1 wasconducted prior to permanent implantation in one subject. Indication forimplantation was for treatment of pain. Stimulation intensity rangedbetween 0.1-10.0 mA, frequencies ranged between 5-60 Hz, and pulse widthwas at 210 or 450 ps. After 7 days, one Boston Scientific Artisan(Valencia, Calif.) 16-electrode epidural array and one Boston ScientificPrecision Plus Spinal Cord Stimulator (Valencia, Calif.) were implantedencompassing C5 to T1. The effects of various combinations ofstimulation parameters were assessed to obtain the best response forhand function. Stimulation intensity ranged between 0.13.0 mA,frequencies ranged between 5-60 Hz, and pulse width was at 210 or 450ps.

Outcomes were averaged across all observations in a given phase/periodfor each subject. Group mean changes across subjects in grip strength,EMG amplitude, ARAT score and ASIA score from baseline over the 5 phaseswere compared using a non-parametric repeated measure analysis ofvariance model using re-sampling. A two sided p value of p<0.05 wasconsidered significant. Means±standard error of the mean (SEM) arereported.

Methods Subject Profiles

The University of California, Los Angeles Institutional Review Boardapproved all procedures. Subjects were enrolled based on the enrollmentcriteria of traumatic cervical injury, ASIA B, greater than 1 year frominjury, and stable motor function as documented by sequential clinicalexams. The clinical profiles of the subjects upon enrollment into thisstudy are as follows: Subject A was a 20 year old male who suffered a C6SCI after a motor vehicle accident and was 36 months from initialinjury; Subject B was a 18 year old male who suffered a C5 SCI after adiving accident and was 18 months from initial injury; Subject C was a21 year old female who suffered a C2 SCI after a motor vehicle accidentand was 45 months from initial injury; Subject D was a 20 year old malewho suffered a C5 SCI sustained during football game and was 30 monthsfrom initial injury; Subject E was a 18 year old male who suffered a C5SCI after a diving accident and was 24 months from initial injury; andSubject F was an 18 year old female with C6 SCI sustained after a fallfrom height and was 18 months from initial injury. Magnetic resonanceimaging was obtained in all subjects to confirm location and descriptionof injury (FIG. 5). Baseline clinical scores (ARAT, ASIA) were assessedprior to and throughout the study (FIG. 1, panel I).

Hand Testing

Voluntary motor control data were assessed using a handgrip forcemeasurement device. Motor assessment was conducted on the arm that wasmost functional post-injury regardless of the pre-injury dominant side.Briefly, the device measures displacement against springs with a rangein spring constants. Measurement of maximal voluntary contraction wasconducted by asking the subject to contract his/her hand against thesprings to maximally displace the handgrip. The contraction lasted forapproximately 3-5 sec and was repeated twice. For handoscillation/repeated contractions, the subject was asked to contract andrelease the hand as fast as possible above and below two lines on acomputer screen that was preset at 12.5 and 37.5% of maximum voluntarycontraction. The number of completed contraction-release sequencesacross the lines was determined. For hand control, the subject was askedto trace a sinusoidal wave (0.15 Hz) that appeared on the computerscreen by squeezing the handgrip. The percentage of data points thatfell inside a circular window at a sampling of 15 Hz was determined. TheEMG data were collected via surface electrodes placed unilaterally onthe biceps brachii (biceps), triceps brachii (triceps), brachioradialis(Brac), extensor digitorum (ED), flexor digitorum (FD), thenar, andhypothenar (H. Thenar) muscles. Stimulation and data collection wasobtained using the Konigsberg EMG system (Konigsberg, Pasadena, Calif.).Functional assessments by validated assessment tools were performedweekly during each phase of study: American Spinal Injury Assessment(ASIA), and Action Research Arm Test (ARAT) (Carroll (1965) J. ChronicDis., 18: 479-491).

ARAT was selected due its focus on arm motor ability and because it hasbeen validated and applied in the SCI setting. Scoring was conducted bytwo experienced examiners who were not informed of the treatment phase(blinded). If discrepancy existed between the scores, the exam wasrepeated and a consensus reached.

Prior to initiation of the study, the stability of hand function andtraining effect of utilizing the handgrip was assessed over the courseof 6 weeks during which the subjects were tested and trained with thehandgrip twice/week. In all subjects assessed, there was no improvementin hand function during this baseline testing (FIG. 6). Testing andtraining during this assessment period involved asking the subject tomaximally contract the hand using the handgrip device. A total of 9-36maximum hand contractions were performed during each session over aperiod of one to two hours.

pcEMC and fEMC

The transcutaneous stimulation device is non-invasive. A surfacestimulation cathode electrode was attached on the dorsal aspect of theneck (C5 area) and the grounding electrode was placed on the anteriorsuperior iliac spine. Stimulation parameters ranged from 5-30 Hz and20-100 mA. Varying combinations of these stimulation parameters weresystematically assessed to obtain optimum facilitation of voluntary handcontraction by identification of the relative activation levels of themotor pools studied (data not shown). During each of the three treatmentperiods (Phases 2-4) a series of nine 3.5-sec maximum hand grip strengthtests were performed per treatment session. In each session of Phase 2,three contractions were performed without pcEmc, followed by three inthe presence of pcEmc (twice weekly at 30 Hz and 20-40 mA), followed bythree without pcEmc. The same pcEmc protocol was followed during Phases2-4. The duration of pcEmc during each testing session was approximately15-30 min. The total number of maximum hand contractions was 9-36 andeach session lasted 1 to 2 hours. During pcEMC, the subjects reported anon-painful, tingling sensation down the arms at the higher stimulationintensities at the site of stimulation with some associated tonicparaspinal muscle contractions at the neck.

From the midpoint of the Phase 1 to the end of Phase 4 all subjects wereinformed that they would receive either a placebo or the monoaminergicagonist buspirone. All subjects and testers were blinded as to whichtreatment was administered and were given buspirone (7.5 mg buspironetwice daily for 2 weeks beginning the day before biweekly testing)during Phase 3 and a placebo during Phases 1, 2, and 4.

eEMC

Planning for surgical placement of spinal cord epidural stimulator(eEmc) on subject E was initiated prior to study enrollment. Thecriteria for selection was based on Federal Drug Administration approveduse for the treatment of pain and Dr. Lu and two other physiciansconfirmed the indication for implantation. A temporary trial with two16-contact percutaneous epidural leads (Linear Lead, Boston Scientific,Valencia, Calif.) spanning C2 to T1 was conducted prior to permanentimplantation. After implantation, testing was conducted over a 2-hoursession to assess the efficacy for improving hand function. Stimulationamplitude ranged between 0.110.0 mA, frequencies ranged between 5-60 Hz,and pulse width was at 210 or 450 ps. Total time of stimulation was 30min.

After 7 days of confirmed efficacy in the treatment of pain, one BostonScientific Artisan (Valencia, Calif.) 16-electrode epidural array andone Boston Scientific Precision Plus Spinal Cord Stimulator (Valencia,Calif.) were implanted encompassing C5 to T1. The effects of variouscombinations of stimulation parameters were assessed to obtain the bestresponse for hand function. A combined total of 60 testing sessions wereconducted on Subject E over the course of 20 months (epidural implantoccurred between testing session 21 and 22). Each testing session lastedup to 180 min. During each testing session, stimulation duration lastedbetween 30-120 min. Stimulation amplitude ranged between 0.1-3.0 mA,frequencies ranged between 5-60 Hz, and pulse width was at 210 or 450ps. During low intensity eEMC, the subject reported a tingling sensationat the neck that migrated toward the arms and hands. At the optimalstimulation parameters, the subject reported the perception of increasedhand strength and control similar to pre-injury ability.

Statistical Analysis

Outcome measures (grip strength force, EMG amplitude, ARAT score, ASIAscore) were averaged across all observations in a given Phase for eachsubject. Using these values, group mean changes across subjects for eachoutcome measure from baseline over the 5 phases were compared using anon-parametric repeated measure analysis of variance model usingre-sampling (bootstrap). The repeated measure mixed model takes intoaccount the correlation across time on the same subjects. A two-sided pvalue of p<0.05 was considered significant. Standard error of the mean(SEM) are reported. Individual mean profiles and the correspondingwithin person SEM also are reported.

It is understood that the examples and embodiments described herein arefor illustrative purposes only and that various modifications or changesin light thereof will be suggested to persons skilled in the art and areto be included within the spirit and purview of this application andscope of the appended claims. All publications, patents, and patentapplications cited herein are hereby incorporated by reference in theirentirety for all purposes.

What is claimed is:
 1. A method of improving motor control and/orstrength in a hand of a subject with a neuromotor disorder affectingmotor control of the hand, said method comprising: neuromodulating thecervical spinal cord of said subject by administering transcutaneousstimulation to the cervical spinal cord or a region thereof; and/orneuromodulating the cervical spinal cord of said subject byadministering epidural stimulation to the cervical spinal cord or aregion thereof; and/or by administering to said subject at least onemonoaminergic agonist.
 2. The method of claim 1, wherein said methodcomprises administering transcutaneous stimulation to the cervicalspinal cord or a region thereof.
 3. The method of claim 1, wherein saidmethod comprises administering epidural stimulation to the cervicalspinal cord or a region thereof.
 4. The method of claim 1, wherein saidmethod comprises administering a monoaminergic agonist to said subject.5. The method of claim 1, wherein said method comprises administeringtranscutaneous stimulation to the cervical spinal cord or a regionthereof in conjunction with administration of a monoaminergic agonist.6. The method of claim 1, wherein said method comprises administeringepidural stimulation to the cervical spinal cord or a region thereof inconjunction with administration of a monoaminergic agonist.
 7. Themethod of claim 1, wherein said method comprises administeringtranscutaneous stimulation to the cervical spinal cord or a regionthereof in conjunction with epidural stimulation of the cervical spinalcord or a region thereof.
 8. The method of claim 1, wherein said methodcomprises administering transcutaneous stimulation to the cervicalspinal cord or a region thereof in conjunction with epidural stimulationof the cervical spinal cord or a region thereof in conjunction withadministration of a monoaminergic agonist to said subject.
 9. The methodaccording to any one of claims 1, 2, 5, 7, and 8, wherein saidtranscutaneous stimulation is at a frequency ranging from about 3 Hz, orfrom about 5 Hz, or from about 10 Hz to about 100 Hz, or to about 80 Hz,or to about 40 Hz, or from about 3 Hz or from about 5 Hz to about 80 Hz,or from about 5 Hz to about 30 Hz, or to about 40 Hz, or to about 50 Hz.10. The method according to any one of claims 1, 2, 5, and 7-9, whereinsaid transcutaneous stimulation is applied at an intensity ranging fromabout 10 mA to about 150 mA, or from about 20 mA to about 50 mA or toabout 100 mA, or from about 20 mA or from about 30 mA, or from about 40mA to about 50 mA, or to about 60 mA, or to about 70 mA or to about 80mA.
 11. The method according to any one of claims 1, 2, 5, and 7-10,wherein said transcutaneous stimulation is at a frequency and amplitudesufficient to improve hand strength and/or fine hand control.
 12. Themethod according to any one of claims 1, 2, 5, and 7-11, wherein saidtranscutaneous stimulation is applied to the dorsal aspect of the neckin the area of C5.
 13. The method according to any one of claims 1, 3,and 6-12, wherein said epidural stimulation is at a frequency rangingfrom about 3 Hz, or from about 5 Hz, or from about 10 Hz to about 100Hz, or to about 80 Hz, or to about 40 Hz, or from about 3 Hz or fromabout 5 Hz to about 80 Hz, or from about 5 Hz to about 30 Hz, or toabout 40 Hz, or to about 50 Hz.
 14. The method according to any one ofclaims 1, 3, and 6-13, wherein said epidural stimulation is at anamplitude ranging from 0.05 mA to about 30 mA, or from about 0.1 mA toabout 20 mA, or from about 0.1 mA to about 15 mA or to about 10 mA. 15.The method according to any one of claims 1, 3, and 6-14, wherein saidpulse width ranges from about 150 μs to about 600 μs, or from about 200μs to about 500 μs, or from about 200 μs to about 450 μs.
 16. The methodaccording to any one of claims 1, 3, and 6-15, wherein said epiduralstimulation is at a frequency and amplitude sufficient to improve handstrength and/or fine hand control.
 17. The method according to any oneof claims 1, 3, and 6-16, wherein said epidural stimulation is appliedparaspinally over vertebrae spanning C2 to T1.
 18. The method accordingto any one of claims 1, 3, and 6-16, wherein said epidural stimulationis applied paraspinally over vertebrae spanning C5 to T1.
 19. The methodaccording to any one of claims 1, 3, and 6-18, wherein said epiduralstimulation is applied via a permanently implanted electrode array. 20.The method of claim 19, wherein said electrode array is a parylene basedmicroelectrode implant.
 21. The method according to any one of claims 1,4, 5, 6, and 8-20, wherein said at least one monoaminergic agonistcomprises an agent selected from the group consisting of a serotonergicdrug, a dopaminergic drug, a noradrenergic drug, a GABAergic drug, and aglycinergic drug.
 22. The method of claim 21, wherein said agent isselected from the group consisting of8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT),4-(benzodioxan-5-yl)1-(indan-2-yl)piperazine (S15535),N-{2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl}-N-(2-pyridinyl)cyclo-hexanecarboxamide(WAY 100.635), Quipazine, Ketanserin, 4-amino-(6-chloro-2-pyridyl)-1piperidine hydrochloride (SR 57227A), Ondanesetron, Buspirone,Methoxamine, Prazosin, Clonidine, Yohimbine,6-chloro-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol(SKF-81297),7-chloro-3-methyl-1-phenyl-1,2,4,5-tetrahydro-3-benzazepin-8-ol(SCH-23390), Quinpirole, and Eticlopride.
 23. The method of claim 21,wherein said monoaminergic agonist is buspirone.
 24. The methodaccording to any one of claims 1, 5, 6, 8, and 6-23, wherein acombination of transcutaneous and/or epidural stimulation andmonoaminergic agonist provides a synergistic improvement in handstrength and/or fine hand control.
 25. The method according to any oneof claims 1-24, wherein said subject is a human.
 26. The methodaccording to any one of claims 1-25, wherein said subject has a spinalcord injury.
 27. The method of claim 26, wherein said spinal cord injuryis clinically classified as motor complete.
 28. The method of claim 26,wherein said spinal cord injury is clinically classified as motorincomplete.
 29. The method according to any one of claims 1-25, whereinsaid subject has an ischemic brain injury.
 30. The method of claim 29,wherein said ischemic brain injury is brain injury from stroke or acutetrauma.
 31. The method according to any one of claims 1-25, wherein saidsubject has a neurodegenerative pathology.
 32. The method of claim 31,wherein said neurodegenerative pathology is associated with a conditionselected from the group consisting of Parkinson's disease, Huntington'sdisease, Alzhiemer's disease, amyotrophic lateral sclerosis (ALS),primary lateral sclerosis (PLS), dystonia, and cerebral palsy.
 33. Themethod according to any one of claims 1-32, wherein the stimulation isunder control of the subject.
 34. The method according to any one ofclaims 1-33, wherein said method further comprises physical training ofsaid subject.
 35. The method of claim 34, wherein said physical trainingcomprises hand contraction against a resistance.
 36. The methodaccording to any one of claims 34-35, wherein said physical trainingcomprises tracing a displayed pattern by hand manipulation of a handcontroller.
 37. An electrical stimulator configured to induce epiduraland/or transcutaneous electrical stimulation in the cervical region of asubject according to any one of claims 1-20.